The present invention relates to a sophorolid, wherein the sophorolid is produced by a method involving reacting a compound of formula I
with a compound of formula II
wherein    R1 and R2 are H, C1-C18 alkyl, C3-C18 alkenyl, C3-C10 cycloalkyl, phenyl, or C1 through C18 acyl or alkoxycarbonyl,    R1 and R2 are not both acyl,    R3 is H, CH3, CH2-phenyl, CH2—C6H4—OH, CH2CO2H, CH2CH2CO2H, CH(CH3)2, CH2CH(CH3)2, CH(CH3)CH2CH3, CH2OH, CH(CH3)OH, CH2CH2CH2CH2NH2, CH2CH2CONH2, CH2CONH2, CH2—C3N2H3(histidine), CH2CH2CH2NHC(NH)NH2, CH2CH2SCH3,    R2 and R3 may be joined in a ring,    R4 is H, C1-C18 alkyl, C3-C18 alkenyl, C3-C10 cycloalkyl, or phenyl,    n is 0-6,    R5 and R6 are H, C1-C18 alkyl, C3-C18 alkenyl, C3-C10 cycloalkyl, or phenyl, and    X is C1-C18 alkyl or C1-C18 alkenyl;optionally followed by acidolytic deprotection (treating with an acid) or hydrogenolytic deprotection (treating with a hydrogenolysis catalyst) which removes one of the groups R1 or R2 and replaces it with hydrogen. In addition, the present invention relates to a sophorolipid containing composition containing a carrier and at least one sophorolipid described above.
Sophorolipids (SL) are hydroxy fatty acid glycosides that can be produced in good yields (e.g., around 100 g/L) by microbial fermentation of a wide variety of feedstocks (Asmer, H.-J., et al., J. Am. Oil. Chem. Soc., 65: 1460-1466 (1988); Cavalero, D. A., and D. G. Cooper, J. Biotech., 103: 31-41 (2003)). Agricultural byproducts such as tallow or soy molasses can be converted into these interesting glycolipids (Solaiman, D. K. Y., et al., Biotech. Lett., 26: 1241-1245 (2004)). The material as produced consists of a number of closely related variants, including a lactone (closed chain) and an open-chain form, each of which may bear up to two acetyl groups. Furthermore, depending on the feedstock, the predominantly C-18 lipid chain can be predominantly a stearic or oleic acid derivative or a mixture. The crude material possesses surfactant activity and might be used as an eco-friendly detergent. Its structural multiplicity, however, complicates attempts to correlate molecular shape with surfactant behavior. We have found ways in which the fundamental sophorolipid skeleton can be chemically modified to increase its utility as a surfactant, in particular by increasing the water-solubility of SLs with charged head groups.